Abstract 807: Predictive biomarkers for Bevacizumab activity in recurrent glioblastoma: A single institution study

Glioblastoma Multiforme (GBM) is an aggressive type of astrocytoma and the most common malignant brain tumor in adults. Bevacizumab is a recombinant monoclonal antibody that targets VEGF-A. VEGF is regulated by the hypoxia-inducible-factor (HIF-1α) pathway, with the tumor suppressor gene TP53 as one of the key regulating factors. Our study examines the relevance of various genetic mutations of the HIF-1α pathway and their predictive significance in patients diagnosed with recurrent GBM and treated with bevacizumab. A total of 41 patients diagnosed with recurrent GBM and treated with Bevacizumab at Virginia Commonwealth University from January 1990 through November 2018 were included in our study. Our study cohort consists of 56.1% males and 43.9% females, with an average age of 59.9 (SD 12.1), and 68.3% were Caucasian. The majority (90%) of the cohort were classified as de novo cases of GBM. The overall survival (OS) was 172.5 days (95% CI: 122.0, 218.5), with a minimum of 11 days and maximum of 904 days measured from the date of the first bevacizumab treatment to the date of death. The majority of patients (70.7%) responded to treatment, with 61% exhibiting a partial response and 9.8% exhibiting a complete response. The median first response to treatment (FRT) was 34 days (95% CI: 21, 40), with a minimum of 2 days and maximum of 76. All patients died during the follow-up period. Survival analyses for OS, along with FRT, were both performed with Kaplan-Meier curves generated individually. We have examined the clinical characteristics of our study cohort and are currently examining the genetic characteristics of the tumors in our cohort. At the time of the conference we will have updated genomic and radiographic data in addition to the current detailed clinical data. Citation Format: Marcin Dragan, Matthew Carli, Mark Malkin, Victor Yazbeck. Predictive biomarkers for Bevacizumab activity in recurrent glioblastoma: A single institution study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 807.